CVEvulnerability

CVE-2021-29991

8.1 HIGH Published 2021-11-03 Modified 2026-06-17 Official page ↗
Status
Modified
Published
2021-11-03
Last modified
2026-06-17
Assigner
[email protected]
CVSS 3.1 ([email protected])
8.1 HIGH — CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
CVSS 2.0 ([email protected])
5.8 MEDIUM — AV:N/AC:M/Au:N/C:P/I:P/A:N
Weaknesses
CWE-444

Description

Firefox incorrectly accepted a newline in a HTTP/3 header, interpretting it as two separate headers. This allowed for a header splitting attack against servers using HTTP/3. This vulnerability affects Firefox < 91.0.1 and Thunderbird < 91.0.1.

Affected configurations

• mozilla firefox (< 91.0.1) • mozilla thunderbird (< 91.0.1)

Related

Weakness · CWE (1)

  • CWE-444 Inconsistent Interpretation of HTTP Requests weakness

References